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Method And Apparatus For Bridge Construction - PDF

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Method And Apparatus For Bridge Construction - PDF Powered By Docstoc
					
				
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Description: The present invention is directed to an apparatus for use in constructing a bridge and a method for constructing a bridge.BACKGROUND OF THE INVENTION The main elements of the type of bridge to which the invention is directed are: (a) a substructure; and (b) a superstructure. A substructure is comprised of (1) foundations and (2) piers. The foundations are the components of the substructure that engage or interact with the earth to support the bridge structure. A foundation can be constructed of one or more piles,one or more concrete drilled shafts, one or more concrete mats, and combinations thereof. Presently, piles include precast concrete piles and steel piles. The piers are the components of the substructure that transfer the bridge structural loads to thefoundations. A pier can be constructed of columns, struts, pile caps, pier caps, and combinations thereof. Presently, columns include cast in place columns, precast concrete columns, and steel columns. A superstructure carries the traffic load (vehicular, rail, and/or pedestrian) on the bridge. A superstructure can be constructed using girders that each typically span the distance between two adjacent piers. Presently, girders includeprecast concrete girders, cast in place girders, precast concrete box girders, segmental box girders, steel girders, and steel box girders. Some superstructures use two or more different types of girders. Presently, there are several methods of constructing a bridge comprised of a substructure and a superstructure (hereinafter referred to as a "bridge") in situations in which there is limited access from the ground. Characteristic of each methodis the use of one or more conventional cranes that are each capable of rotating a boom about horizontal and vertical axes to either move an element of bridge into place or manipulate a tool that is used in constructing the bridge. One method employs acrane that is positioned on top of and near the end of the existing superstructu